(opensource; gets Android notifications through Growl), Last.fm scrobbler (for music), Adium IM (menubar theme used: Adium Twitbar), Caffeine (prevents the Mac from sleeping), Dropbox, (helps display a variety of info on your desktop), Macfusion (Filesystem mount plugin), and Anxiety (light weight to do manager that syncs with iCal and Mail).
(From Bharadhwaj Narayanan)